content: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2013, by Object Refinery Limited and Contributors.
   *
   * Project Info:  http://www.jfree.org/jfreechart/index.html
   *
   * This library is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA.
   *
   * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
   * Other names may be trademarks of their respective owners.]
   *
   * -------------
   * XYSeries.java
   * -------------
   * (C) Copyright 2001-2012, Object Refinery Limited and Contributors.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited);
   * Contributor(s):   Aaron Metzger;
   *                   Jonathan Gabbai;
   *                   Richard Atkinson;
   *                   Michel Santos;
   *                   Ted Schwartz (fix for bug 1955483);
   *
   * Changes
   * -------
   * 15-Nov-2001 : Version 1 (DG);
   * 03-Apr-2002 : Added an add(double, double) method (DG);
   * 29-Apr-2002 : Added a clear() method (ARM);
   * 06-Jun-2002 : Updated Javadoc comments (DG);
   * 29-Aug-2002 : Modified to give user control over whether or not duplicate
   *               x-values are allowed (DG);
   * 07-Oct-2002 : Fixed errors reported by Checkstyle (DG);
   * 11-Nov-2002 : Added maximum item count, code contributed by Jonathan
   *               Gabbai (DG);
   * 26-Mar-2003 : Implemented Serializable (DG);
   * 04-Aug-2003 : Added getItems() method (DG);
   * 15-Aug-2003 : Changed 'data' from private to protected, added new add()
   *               methods with a 'notify' argument (DG);
   * 22-Sep-2003 : Added getAllowDuplicateXValues() method (RA);
   * 29-Jan-2004 : Added autoSort attribute, based on a contribution by
   *               Michel Santos - see patch 886740 (DG);
   * 03-Feb-2004 : Added indexOf() method (DG);
   * 16-Feb-2004 : Added remove() method (DG);
   * 18-Aug-2004 : Moved from org.jfree.data --> org.jfree.data.xy (DG);
   * 21-Feb-2005 : Added update(Number, Number) and addOrUpdate(Number, Number)
   *               methods (DG);
   * 03-May-2005 : Added a new constructor, fixed the setMaximumItemCount()
   *               method to remove items (and notify listeners) if necessary,
   *               fixed the add() and addOrUpdate() methods to handle unsorted
   *               series (DG);
   * ------------- JFreeChart 1.0.x ---------------------------------------------
   * 11-Jan-2005 : Renamed update(int, Number) --> updateByIndex() (DG);
   * 15-Jan-2007 : Added toArray() method (DG);
   * 31-Oct-2007 : Implemented faster hashCode() (DG);
   * 22-Nov-2007 : Reimplemented clone() (DG);
   * 01-May-2008 : Fixed bug 1955483 in addOrUpdate() method, thanks to
   *               Ted Schwartz (DG);
   * 24-Nov-2008 : Further fix for 1955483 (DG);
   * 06-Mar-2009 : Added minX, maxX, minY and maxY fields (DG);
   * 10-Jun-2009 : Make clones to isolate XYDataItem instances used
   *               for data storage (DG);
   * 16-Jun-2012 : Removed JCommon dependencies (DG);
   * 
   */
  
  package org.jfree.data.xy;
  
  import java.io.Serializable;
  import java.util.Collections;
  import java.util.List;
  
  import org.jfree.chart.util.ObjectUtilities;
  import org.jfree.chart.util.ParamChecks;
  import org.jfree.data.general.Series;
  import org.jfree.data.general.SeriesChangeEvent;
  import org.jfree.data.general.SeriesException;
  
  /**
   * Represents a sequence of zero or more data items in the form (x, y).  By
   * default, items in the series will be sorted into ascending order by x-value,
   * and duplicate x-values are permitted.  Both the sorting and duplicate
   * defaults can be changed in the constructor.  Y-values can be
   * <code>null</code> to represent missing values.
   */
  public class XYSeries extends Series implements Cloneable, Serializable {
  
      /** For serialization. */
      static final long serialVersionUID = -5908509288197150436L;
  
      // In version 0.9.12, in response to several developer requests, I changed
      // the 'data' attribute from 'private' to 'protected', so that others can
      // make subclasses that work directly with the underlying data structure.
  
      /** Storage for the data items in the series. */
      protected List<XYDataItem> data;
  
      /** The maximum number of items for the series. */
      private int maximumItemCount = Integer.MAX_VALUE;
  
      /**
       * A flag that controls whether the items are automatically sorted
       * (by x-value ascending).
       */
      private boolean autoSort;
  
      /** A flag that controls whether or not duplicate x-values are allowed. */
      private boolean allowDuplicateXValues;
  
      /** The lowest x-value in the series, excluding Double.NaN values. */
      private double minX;
  
      /** The highest x-value in the series, excluding Double.NaN values. */
      private double maxX;
  
      /** The lowest y-value in the series, excluding Double.NaN values. */
      private double minY;
  
      /** The highest y-value in the series, excluding Double.NaN values. */
      private double maxY;
  
      /**
       * Creates a new empty series.  By default, items added to the series will
       * be sorted into ascending order by x-value, and duplicate x-values will
       * be allowed (these defaults can be modified with another constructor).
       *
       * @param key  the series key (<code>null</code> not permitted).
       */
      public XYSeries(Comparable key) {
          this(key, true, true);
      }
  
      /**
       * Constructs a new empty series, with the auto-sort flag set as requested,
       * and duplicate values allowed.
       *
       * @param key  the series key (<code>null</code> not permitted).
       * @param autoSort  a flag that controls whether or not the items in the
       *                  series are sorted.
       */
      public XYSeries(Comparable key, boolean autoSort) {
          this(key, autoSort, true);
      }
  
      /**
       * Constructs a new xy-series that contains no data.  You can specify
       * whether or not duplicate x-values are allowed for the series.
       *
       * @param key  the series key (<code>null</code> not permitted).
       * @param autoSort  a flag that controls whether or not the items in the
       *                  series are sorted.
       * @param allowDuplicateXValues  a flag that controls whether duplicate
       *                               x-values are allowed.
       */
      public XYSeries(Comparable key, boolean autoSort,
              boolean allowDuplicateXValues) {
          super(key);
          this.data = new java.util.ArrayList<XYDataItem>();
          this.autoSort = autoSort;
          this.allowDuplicateXValues = allowDuplicateXValues;
          this.minX = Double.NaN;
          this.maxX = Double.NaN;
          this.minY = Double.NaN;
          this.maxY = Double.NaN;
      }
  
      /**
       * Returns the smallest x-value in the series, ignoring any Double.NaN
       * values.  This method returns Double.NaN if there is no smallest x-value
       * (for example, when the series is empty).
       *
       * @return The smallest x-value.
       *
       * @see #getMaxX()
       *
       * @since 1.0.13
       */
      public double getMinX() {
          return this.minX;
      }
  
      /**
       * Returns the largest x-value in the series, ignoring any Double.NaN
       * values.  This method returns Double.NaN if there is no largest x-value
       * (for example, when the series is empty).
       *
       * @return The largest x-value.
       *
       * @see #getMinX()
       *
       * @since 1.0.13
       */
      public double getMaxX() {
          return this.maxX;
      }
  
      /**
       * Returns the smallest y-value in the series, ignoring any null and
       * Double.NaN values.  This method returns Double.NaN if there is no
       * smallest y-value (for example, when the series is empty).
       *
       * @return The smallest y-value.
       *
       * @see #getMaxY()
       *
       * @since 1.0.13
       */
      public double getMinY() {
          return this.minY;
      }
  
      /**
       * Returns the largest y-value in the series, ignoring any Double.NaN
       * values.  This method returns Double.NaN if there is no largest y-value
       * (for example, when the series is empty).
       *
       * @return The largest y-value.
       *
       * @see #getMinY()
       *
       * @since 1.0.13
       */
      public double getMaxY() {
          return this.maxY;
      }
  
      /**
       * Updates the cached values for the minimum and maximum data values.
       *
       * @param item  the item added (<code>null</code> not permitted).
       *
       * @since 1.0.13
       */
      private void updateBoundsForAddedItem(XYDataItem item) {
          double x = item.getXValue();
          this.minX = minIgnoreNaN(this.minX, x);
          this.maxX = maxIgnoreNaN(this.maxX, x);
          if (item.getY() != null) {
              double y = item.getYValue();
              this.minY = minIgnoreNaN(this.minY, y);
              this.maxY = maxIgnoreNaN(this.maxY, y);
          }
      }
  
      /**
       * Updates the cached values for the minimum and maximum data values on
       * the basis that the specified item has just been removed.
       *
       * @param item  the item added (<code>null</code> not permitted).
       *
       * @since 1.0.13
       */
      private void updateBoundsForRemovedItem(XYDataItem item) {
          boolean itemContributesToXBounds = false;
          boolean itemContributesToYBounds = false;
          double x = item.getXValue();
          if (!Double.isNaN(x)) {
              if (x <= this.minX || x >= this.maxX) {
                  itemContributesToXBounds = true;
              }
          }
          if (item.getY() != null) {
              double y = item.getYValue();
              if (!Double.isNaN(y)) {
                  if (y <= this.minY || y >= this.maxY) {
                      itemContributesToYBounds = true;
                  }
              }
          }
          if (itemContributesToYBounds) {
              findBoundsByIteration();
          }
          else if (itemContributesToXBounds) {
              if (getAutoSort()) {
                  this.minX = getX(0).doubleValue();
                  this.maxX = getX(getItemCount() - 1).doubleValue();
              }
              else {
                  findBoundsByIteration();
              }
          }
      }
  
      /**
       * Finds the bounds of the x and y values for the series, by iterating
       * through all the data items.
       *
       * @since 1.0.13
       */
      private void findBoundsByIteration() {
          this.minX = Double.NaN;
          this.maxX = Double.NaN;
          this.minY = Double.NaN;
          this.maxY = Double.NaN;
          for (XYDataItem item : this.data) {
              updateBoundsForAddedItem(item);
          }
      }
  
      /**
       * Returns the flag that controls whether the items in the series are
       * automatically sorted.  There is no setter for this flag, it must be
       * defined in the series constructor.
       *
       * @return A boolean.
       */
      public boolean getAutoSort() {
          return this.autoSort;
      }
  
      /**
       * Returns a flag that controls whether duplicate x-values are allowed.
       * This flag can only be set in the constructor.
       *
       * @return A boolean.
       */
      public boolean getAllowDuplicateXValues() {
          return this.allowDuplicateXValues;
      }
  
      /**
       * Returns the number of items in the series.
       *
       * @return The item count.
       *
       * @see #getItems()
       */
      @Override
      public int getItemCount() {
          return this.data.size();
      }
  
      /**
       * Returns the list of data items for the series (the list contains
       * {@link XYDataItem} objects and is unmodifiable).
       *
       * @return The list of data items.
       */
      public List<XYDataItem> getItems() {
          return Collections.unmodifiableList(this.data);
      }
  
      /**
       * Returns the maximum number of items that will be retained in the series.
       * The default value is <code>Integer.MAX_VALUE</code>.
       *
       * @return The maximum item count.
       *
       * @see #setMaximumItemCount(int)
       */
      public int getMaximumItemCount() {
          return this.maximumItemCount;
      }
  
      /**
       * Sets the maximum number of items that will be retained in the series.
       * If you add a new item to the series such that the number of items will
       * exceed the maximum item count, then the first element in the series is
       * automatically removed, ensuring that the maximum item count is not
       * exceeded.
       * <p>
       * Typically this value is set before the series is populated with data,
       * but if it is applied later, it may cause some items to be removed from
       * the series (in which case a {@link SeriesChangeEvent} will be sent to
       * all registered listeners).
       *
       * @param maximum  the maximum number of items for the series.
       */
      public void setMaximumItemCount(int maximum) {
          this.maximumItemCount = maximum;
          int remove = this.data.size() - maximum;
          if (remove > 0) {
              this.data.subList(0, remove).clear();
              findBoundsByIteration();
              fireSeriesChanged();
          }
      }
  
      /**
       * Adds a data item to the series and sends a {@link SeriesChangeEvent} to
       * all registered listeners.
       *
       * @param item  the (x, y) item (<code>null</code> not permitted).
       */
      public void add(XYDataItem item) {
          // argument checking delegated...
          add(item, true);
      }
  
      /**
       * Adds a data item to the series and sends a {@link SeriesChangeEvent} to
       * all registered listeners.
       *
       * @param x  the x value.
       * @param y  the y value.
       */
      public void add(double x, double y) {
          add(Double.valueOf(x), Double.valueOf(y), true);
      }
  
      /**
       * Adds a data item to the series and, if requested, sends a
       * {@link SeriesChangeEvent} to all registered listeners.
       *
       * @param x  the x value.
       * @param y  the y value.
       * @param notify  a flag that controls whether or not a
       *                {@link SeriesChangeEvent} is sent to all registered
       *                listeners.
       */
      public void add(double x, double y, boolean notify) {
          add(Double.valueOf(x), Double.valueOf(y), notify);
      }
  
      /**
       * Adds a data item to the series and sends a {@link SeriesChangeEvent} to
       * all registered listeners.  The unusual pairing of parameter types is to
       * make it easier to add <code>null</code> y-values.
       *
       * @param x  the x value.
       * @param y  the y value (<code>null</code> permitted).
       */
      public void add(double x, Number y) {
          add(Double.valueOf(x), y);
      }
  
      /**
       * Adds a data item to the series and, if requested, sends a
       * {@link SeriesChangeEvent} to all registered listeners.  The unusual
       * pairing of parameter types is to make it easier to add null y-values.
       *
       * @param x  the x value.
       * @param y  the y value (<code>null</code> permitted).
       * @param notify  a flag that controls whether or not a
       *                {@link SeriesChangeEvent} is sent to all registered
       *                listeners.
       */
      public void add(double x, Number y, boolean notify) {
          add(Double.valueOf(x), y, notify);
      }
  
      /**
       * Adds a new data item to the series (in the correct position if the
       * <code>autoSort</code> flag is set for the series) and sends a
       * {@link SeriesChangeEvent} to all registered listeners.
       * <P>
       * Throws an exception if the x-value is a duplicate AND the
       * allowDuplicateXValues flag is false.
       *
       * @param x  the x-value (<code>null</code> not permitted).
       * @param y  the y-value (<code>null</code> permitted).
       *
       * @throws SeriesException if the x-value is a duplicate and the
       *     <code>allowDuplicateXValues</code> flag is not set for this series.
       */
      public void add(Number x, Number y) {
          // argument checking delegated...
          add(x, y, true);
      }
  
      /**
       * Adds new data to the series and, if requested, sends a
       * {@link SeriesChangeEvent} to all registered listeners.
       * <P>
       * Throws an exception if the x-value is a duplicate AND the
       * allowDuplicateXValues flag is false.
       *
       * @param x  the x-value (<code>null</code> not permitted).
       * @param y  the y-value (<code>null</code> permitted).
       * @param notify  a flag the controls whether or not a
       *                {@link SeriesChangeEvent} is sent to all registered
       *                listeners.
       */
      public void add(Number x, Number y, boolean notify) {
          // delegate argument checking to XYDataItem...
          XYDataItem item = new XYDataItem(x, y);
          add(item, notify);
      }
  
      /**
       * Adds a data item to the series and, if requested, sends a
       * {@link SeriesChangeEvent} to all registered listeners.
       *
       * @param item  the (x, y) item (<code>null</code> not permitted).
       * @param notify  a flag that controls whether or not a
       *                {@link SeriesChangeEvent} is sent to all registered
       *                listeners.
       */
      public void add(XYDataItem item, boolean notify) {
          ParamChecks.nullNotPermitted(item, "item");
          item = item.copy();
          if (this.autoSort) {
              int index = Collections.binarySearch(this.data, item);
              if (index < 0) {
                  this.data.add(-index - 1, item);
              }
              else {
                  if (this.allowDuplicateXValues) {
                      // need to make sure we are adding *after* any duplicates
                      int size = this.data.size();
                      while (index < size && item.compareTo(
                              this.data.get(index)) == 0) {
                          index++;
                      }
                      if (index < this.data.size()) {
                          this.data.add(index, item);
                      }
                      else {
                          this.data.add(item);
                      }
                  }
                  else {
                      throw new SeriesException("X-value already exists.");
                  }
              }
          }
          else {
              if (!this.allowDuplicateXValues) {
                  // can't allow duplicate values, so we need to check whether
                  // there is an item with the given x-value already
                  int index = indexOf(item.getX());
                  if (index >= 0) {
                      throw new SeriesException("X-value already exists.");
                  }
              }
              this.data.add(item);
          }
          updateBoundsForAddedItem(item);
          if (getItemCount() > this.maximumItemCount) {
              XYDataItem removed = this.data.remove(0);
              updateBoundsForRemovedItem(removed);
          }
          if (notify) {
              fireSeriesChanged();
          }
      }
  
      /**
       * Deletes a range of items from the series and sends a
       * {@link SeriesChangeEvent} to all registered listeners.
       *
       * @param start  the start index (zero-based).
       * @param end  the end index (zero-based).
       */
      public void delete(int start, int end) {
          this.data.subList(start, end + 1).clear();
          findBoundsByIteration();
          fireSeriesChanged();
      }
  
      /**
       * Removes the item at the specified index and sends a
       * {@link SeriesChangeEvent} to all registered listeners.
       *
       * @param index  the index.
       *
       * @return The item removed.
       */
      public XYDataItem remove(int index) {
          XYDataItem removed = this.data.remove(index);
          updateBoundsForRemovedItem(removed);
          fireSeriesChanged();
          return removed;
      }
  
      /**
       * Removes an item with the specified x-value and sends a
       * {@link SeriesChangeEvent} to all registered listeners.  Note that when
       * a series permits multiple items with the same x-value, this method
       * could remove any one of the items with that x-value.
       *
       * @param x  the x-value.
  
       * @return The item removed.
       */
      public XYDataItem remove(Number x) {
          return remove(indexOf(x));
      }
  
      /**
       * Removes all data items from the series and sends a
       * {@link SeriesChangeEvent} to all registered listeners.
       */
      public void clear() {
          if (this.data.size() > 0) {
              this.data.clear();
              this.minX = Double.NaN;
              this.maxX = Double.NaN;
              this.minY = Double.NaN;
              this.maxY = Double.NaN;
              fireSeriesChanged();
          }
      }
  
      /**
       * Return the data item with the specified index.
       *
       * @param index  the index.
       *
       * @return The data item with the specified index.
       */
      public XYDataItem getDataItem(int index) {
          XYDataItem item = this.data.get(index);
          return item.copy();
      }
  
      /**
       * Return the data item with the specified index.
       *
       * @param index  the index.
       *
       * @return The data item with the specified index.
       *
       * @since 1.0.14
       */
      XYDataItem getRawDataItem(int index) {
          return this.data.get(index);
      }
  
      /**
       * Returns the x-value at the specified index.
       *
       * @param index  the index (zero-based).
       *
       * @return The x-value (never <code>null</code>).
       */
      public Number getX(int index) {
          return getRawDataItem(index).getX();
      }
  
      /**
       * Returns the y-value at the specified index.
       *
       * @param index  the index (zero-based).
       *
       * @return The y-value (possibly <code>null</code>).
       */
      public Number getY(int index) {
          return getRawDataItem(index).getY();
      }
  
      /**
       * A function to find the minimum of two values, but ignoring any
       * Double.NaN values.
       *
       * @param a  the first value.
       * @param b  the second value.
       *
       * @return The minimum of the two values.
       */
      private double minIgnoreNaN(double a, double b) {
          if (Double.isNaN(a)) {
              return b;
          }
          if (Double.isNaN(b)) {
              return a;
          }
          return Math.min(a, b);
      }
  
      /**
       * A function to find the maximum of two values, but ignoring any
       * Double.NaN values.
       *
       * @param a  the first value.
       * @param b  the second value.
       *
       * @return The maximum of the two values.
       */
      private double maxIgnoreNaN(double a, double b) {
          if (Double.isNaN(a)) {
              return b;
          }
          if (Double.isNaN(b)) {
              return a;
          }
          return Math.max(a, b);
      }
  
      /**
       * Updates the value of an item in the series and sends a
       * {@link SeriesChangeEvent} to all registered listeners.
       *
       * @param index  the item (zero based index).
       * @param y  the new value (<code>null</code> permitted).
       *
       * @since 1.0.1
       */
      public void updateByIndex(int index, Number y) {
          XYDataItem item = getRawDataItem(index);
          // figure out if we need to iterate through all the y-values
          boolean iterate = false;
          double oldY = item.getYValue();
          if (!Double.isNaN(oldY)) {
              iterate = oldY <= this.minY || oldY >= this.maxY;
          }
          item.setY(y);
  
          if (iterate) {
              findBoundsByIteration();
          }
          else if (y != null) {
              double yy = y.doubleValue();
              this.minY = minIgnoreNaN(this.minY, yy);
              this.maxY = maxIgnoreNaN(this.maxY, yy);
          }
          fireSeriesChanged();
      }
  
      /**
       * Updates an item in the series.
       *
       * @param x  the x-value (<code>null</code> not permitted).
       * @param y  the y-value (<code>null</code> permitted).
       *
       * @throws SeriesException if there is no existing item with the specified
       *         x-value.
       */
      public void update(Number x, Number y) {
          int index = indexOf(x);
          if (index < 0) {
              throw new SeriesException("No observation for x = " + x);
          }
          updateByIndex(index, y);
      }
  
      /**
       * Adds or updates an item in the series and sends a
       * {@link SeriesChangeEvent} to all registered listeners.
       *
       * @param x  the x-value.
       * @param y  the y-value.
       *
       * @return The item that was overwritten, if any.
       *
       * @since 1.0.10
       */
      public XYDataItem addOrUpdate(double x, double y) {
          return addOrUpdate(Double.valueOf(x), Double.valueOf(y));
      }
  
      /**
       * Adds or updates an item in the series and sends a
       * {@link SeriesChangeEvent} to all registered listeners.
       *
       * @param x  the x-value (<code>null</code> not permitted).
       * @param y  the y-value (<code>null</code> permitted).
       *
       * @return A copy of the overwritten data item, or <code>null</code> if no
       *         item was overwritten.
       */
      public XYDataItem addOrUpdate(Number x, Number y) {
          // defer argument checking
          return addOrUpdate(new XYDataItem(x, y));
      }
  
      /**
       * Adds or updates an item in the series and sends a
       * {@link SeriesChangeEvent} to all registered listeners.
       *
       * @param item  the data item (<code>null</code> not permitted).
       *
       * @return A copy of the overwritten data item, or <code>null</code> if no
       *         item was overwritten.
       *
       * @since 1.0.14
       */
      public XYDataItem addOrUpdate(XYDataItem item) {
          ParamChecks.nullNotPermitted(item, "item");
          if (this.allowDuplicateXValues) {
              add(item);
              return null;
          }
  
          // if we get to here, we know that duplicate X values are not permitted
          XYDataItem overwritten = null;
          int index = indexOf(item.getX());
          if (index >= 0) {
              XYDataItem existing = this.data.get(index);
              overwritten = existing.copy();
              // figure out if we need to iterate through all the y-values
              boolean iterate = false;
              double oldY = existing.getYValue();
              if (!Double.isNaN(oldY)) {
                  iterate = oldY <= this.minY || oldY >= this.maxY;
              }
              existing.setY(item.getY());
  
              if (iterate) {
                  findBoundsByIteration();
              }
              else if (item.getY() != null) {
                  double yy = item.getY().doubleValue();
                  this.minY = minIgnoreNaN(this.minY, yy);
                  this.maxY = maxIgnoreNaN(this.maxY, yy);
              }
          }
          else {
              // if the series is sorted, the negative index is a result from
              // Collections.binarySearch() and tells us where to insert the
              // new item...otherwise it will be just -1 and we should just
              // append the value to the list...
              item = item.copy();
              if (this.autoSort) {
                  this.data.add(-index - 1, item);
              }
              else {
                  this.data.add(item);
              }
              updateBoundsForAddedItem(item);
  
              // check if this addition will exceed the maximum item count...
              if (getItemCount() > this.maximumItemCount) {
                  XYDataItem removed = this.data.remove(0);
                  updateBoundsForRemovedItem(removed);
              }
          }
          fireSeriesChanged();
          return overwritten;
      }
  
      /**
       * Returns the index of the item with the specified x-value, or a negative
       * index if the series does not contain an item with that x-value.  Be
       * aware that for an unsorted series, the index is found by iterating
       * through all items in the series.
       *
       * @param x  the x-value (<code>null</code> not permitted).
       *
       * @return The index.
       */
      public int indexOf(Number x) {
          if (this.autoSort) {
              return Collections.binarySearch(this.data, new XYDataItem(x, null));
          }
          else {
              for (int i = 0; i < this.data.size(); i++) {
                  XYDataItem item = this.data.get(i);
                  if (item.getX().equals(x)) {
                      return i;
                  }
              }
              return -1;
          }
      }
  
      /**
       * Returns a new array containing the x and y values from this series.
       *
       * @return A new array containing the x and y values from this series.
       *
       * @since 1.0.4
       */
      public double[][] toArray() {
          int itemCount = getItemCount();
          double[][] result = new double[2][itemCount];
          for (int i = 0; i < itemCount; i++) {
              result[0][i] = this.getX(i).doubleValue();
              Number y = getY(i);
              if (y != null) {
                  result[1][i] = y.doubleValue();
              }
              else {
                  result[1][i] = Double.NaN;
              }
          }
          return result;
      }
  
      /**
       * Returns a clone of the series.
       *
       * @return A clone of the series.
       *
       * @throws CloneNotSupportedException if there is a cloning problem.
       */
      @Override
      public Object clone() throws CloneNotSupportedException {
          XYSeries clone = (XYSeries) super.clone();
          clone.data = ObjectUtilities.deepClone(this.data);
          return clone;
      }
  
      /**
       * Creates a new series by copying a subset of the data in this time series.
       *
       * @param start  the index of the first item to copy.
       * @param end  the index of the last item to copy.
       *
       * @return A series containing a copy of this series from start until end.
       *
       * @throws CloneNotSupportedException if there is a cloning problem.
       */
      public XYSeries createCopy(int start, int end)
              throws CloneNotSupportedException {
  
          XYSeries copy = (XYSeries) super.clone();
          copy.data = new java.util.ArrayList<XYDataItem>();
          if (this.data.size() > 0) {
              for (int index = start; index <= end; index++) {
                  XYDataItem item = this.data.get(index);
                  XYDataItem clone = (XYDataItem) item.clone();
                  try {
                      copy.add(clone);
                  }
                  catch (SeriesException e) {
                      throw new RuntimeException("Unable to add cloned data item.", e);
                  }
              }
          }
          return copy;
  
      }
  
      /**
       * Tests this series for equality with an arbitrary object.
       *
       * @param obj  the object to test against for equality
       *             (<code>null</code> permitted).
       *
       * @return A boolean.
       */
      @Override
      public boolean equals(Object obj) {
          if (obj == this) {
              return true;
          }
          if (!(obj instanceof XYSeries)) {
              return false;
          }
          if (!super.equals(obj)) {
              return false;
          }
          XYSeries that = (XYSeries) obj;
          if (this.maximumItemCount != that.maximumItemCount) {
              return false;
          }
          if (this.autoSort != that.autoSort) {
              return false;
          }
          if (this.allowDuplicateXValues != that.allowDuplicateXValues) {
              return false;
          }
          if (!ObjectUtilities.equal(this.data, that.data)) {
              return false;
          }
          return true;
      }
  
      /**
       * Returns a hash code.
       *
       * @return A hash code.
       */
      @Override
      public int hashCode() {
          int result = super.hashCode();
          // it is too slow to look at every data item, so let's just look at
          // the first, middle and last items...
          int count = getItemCount();
          if (count > 0) {
              XYDataItem item = getRawDataItem(0);
              result = 29 * result + item.hashCode();
          }
          if (count > 1) {
              XYDataItem item = getRawDataItem(count - 1);
              result = 29 * result + item.hashCode();
          }
          if (count > 2) {
              XYDataItem item = getRawDataItem(count / 2);
              result = 29 * result + item.hashCode();
          }
          result = 29 * result + this.maximumItemCount;
          result = 29 * result + (this.autoSort ? 1 : 0);
          result = 29 * result + (this.allowDuplicateXValues ? 1 : 0);
          return result;
      }
  
  }
  
  